HEPData Search

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Measurement of the Z0 Mass and Width with the OPAL Detector at LEP

The OPAL collaboration Akrawy, M.Z. ; Alexander, G. ; Allison, J. ; et al.

Phys.Lett.B 231 (1989) 530-538, 1989.

Inspire Record 282821 DOI 10.17182/hepdata.29757

We report an experimental determination of the cross section for e + e − → hadrons from a scan around the Z 0 pole. On the basis of 4350 hadronic events collected over seven energy points between 89.26 GeV and 93.26 GeV we obtain a mass of m z =91.01±0.05±0.05 GeV, and a total decay width of Γ z =2.60±0.13 GeV. In the context of the standard model t these results imply 3.1 ± 0.4 neutrino generations.

1 data table

Table 1

No description provided.

Determination of the Number of Light Neutrino Species

The ALEPH collaboration Decamp, D. ; Deschizeaux, B. ; Lees, J.P. ; et al.

Phys.Lett.B 231 (1989) 519-529, 1989.

Inspire Record 282904 DOI 10.17182/hepdata.29758

The cross-section for e + e − → hadrons in the vicinity of the Z boson peak has been measured with the ALEPH detector at the CERN Large Electron Positron collider, LEP. Measurements of the Z mass, M z = (91.174±0.070) GeV, the Z width Γ z =(2.68±0.15) GeV, and of the peak hadronic cross-section, σ had peak =(29.3±1.2) nb, are presented. With the constraints of the standard electroweak model, the number of light neutrino species is found to be N v =3.27±0.30. this results rules out of the possibility of a fourth type of light neutrino at 98% CL.

2 data tables

Table 1

Selection from TPC tracks.

Table 2

Selection by calorimeters.

Multiplicity of Charged Particles in Interactions of Oxygen Nuclei With Hydrogen at 3.1-{GeV}/$c$ Momentum

The Alma Ata-Warsaw-Dubna-Tashkent-Tbilisi collaboration Glagolev, V.V. ; Lebedev, R.M. ; Pestova, G.D. ; et al.

Z.Phys.A 345 (1993) 413-424, 1993.

Inspire Record 281736 DOI 10.17182/hepdata.16558

Experimental data on multiplicities of secondary charged particles in interactions of oxygen nuclei in a hydrogen bubble chamber at the incident momentum of 3.1 A GeV/c are presented and discussed. Multiplicity correlations are studied in details and it is shown that the character of these correlations is strongly influenced by the electric charge and baryon number conservation. Topologies and probabilities of different channels of fragmentation are determined for projectile oxygen nuclei. It is established that channels with production of helium nuclei play an important role in the processes of multifragment break-up of oxygen nuclei. Comparison of the experimental data with predictions of the cascadefragmentation-evaporation model has shown that the model provide the qualitative description of the considerable amount of experimental observations.

3 data tables

Table 1

FRAGB-fragments of a primary nucleus with Z=2, 3, 4, 5, 6, 7, 8.

Table 2

No description provided.

Table 3

Events of the total disintegration of the projectile nucleus: fragments with Z=2, 3, 4, 5, 6, 7, 8 are absent.

K0(S) PRODUCTION IN ANTI-P P INTERACTIONS AT S**(1/2) = 630-GeV AND 1800-GEV

The CDF collaboration Abe, F. ; Amidei, D. ; Apollinari, G. ; et al.

Phys.Rev.D 40 (1989) 3791-3794, 1989.

Inspire Record 287811 DOI 10.17182/hepdata.22999

Measurements of inclusive transverse-momentum spectra for KS0 mesons produced in proton-antiproton collisions at s of 630 and 1800 GeV are presented and compared with data taken at lower energies. The ratio, as a function of pT, of the cross section for KS0 to that for charged hadrons is very similar to what is observed at lower energies. At 1800 GeV, we calculate the strangeness-suppression factor λ=0.40±0.05.

4 data tables

Table 1

Estimated effective cross sections for events which pass the trigger and selection criteria. The uncertainties in these represent the principal source of error in the overall normalisation of the results.

Table 2

Statistical errors only.

Table 3

Statistical errors only.

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INCLUSIVE CHARGED D* PRODUCTION IN 205-GEV/C PI- BE INTERACTIONS

Mooney, P. ; Sarmiento, M. ; Bishop, J.M. ; et al.

Phys.Rev.D 39 (1989) 2494-2498, 1989.

Inspire Record 282266 DOI 10.17182/hepdata.23225

The inclusive cross section for charged-D* production by 205-GeV/c π− mesons incident on a beryllium target was measured with a two-arm spectrometer triggered by prompt muons. Using the mass-difference technique often employed in D* studies, a signal of 31±11 charged D*’s was isolated; it includes contributions from both the D*+ and D*− charged modes in correlation with triggering muons of the proper charge. This corresponds to an inclusive charged-D* production cross section of 220±77−57+77 μb per Be nucleus or 24±9−6+9 μb per nucleon when the cross section is scaled linearly with atomic mass number. The first error is statistical and the second is systematic.

1 data table

Table 1

No description provided.

High Transverse Momentum $\eta$ Production in $\pi^- p$, $\pi^+ p$ and $p p$ Interactions at 280-{GeV}/$c$

The WA70 collaboration Bonesini, M. ; Bonvin, E. ; Booth, P.S. L. ; et al.

Z.Phys.C 42 (1989) 527, 1989.

Inspire Record 267856 DOI 10.17182/hepdata.15526

The inclusive cross sections for η production by the interactions of 280 GeV/c momentum π−, π+, and proton beams in hydrogen have been measured. The kinematical range covered is −0.45<xF<0.45, and 4.0<PT<7.0 GeV/c for FeynmanxF and transverse momentum respectively. The η to π0 cross section ratios are given for the three reactions. The ratio of π−p to π+p cross sections for η production in the above kinematic ranges is 1.22±0.08±0.11.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

Measurement of the Inclusive Jet Cross-Section in anti-p p Collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Amidei, D. ; Apollinari, G. ; et al.

Phys.Rev.Lett. 62 (1989) 613, 1989.

Inspire Record 267999 DOI 10.17182/hepdata.20032

Inclusive jet production at s=1.8 TeV has been measured in the CDF detector at the Fermilab Tevatron p¯p Collider. Jets with transverse energies (Et) up to 250 GeV have been observed. The Et dependence of the inclusive jet cross section is consistent with leading-order quantum-chromodynamic calculations, and comparison with lower-energy data shows deviations from scaling consistent with QCD. A lower limit of 700 GeV (95% confidence level) is placed on the quark compositeness scale parameter Λc associated with an effective contact interaction.

1 data table

Table 1

No description provided.

DOUBLE PROMPT PHOTON PRODUCTION AT HIGH TRANSVERSE MOMENTUM BY pi- ON PROTONS AT 280-GeV/c

The WA70 collaboration Bonvin, E. ; Bopp, R. ; Carroll, L.J. ; et al.

Z.Phys.C 41 (1989) 591, 1989.

Inspire Record 265091 DOI 10.17182/hepdata.15470

A search for pairs of highpT prompt photons produced in hydrogen by a 280 GeV/c incidentπ- beam has been carried out using a fine-grained electromagnetic calorimeter and the Omega spectrometer at the CERN SPS. Clear evidence for the existence of such events is found with a six standard deviation signal forpT>3.0 GeV/c. The cross-sections are consistent with beyond leading order QCD calculations. A discussion on the determination of αs is also presented.

2 data tables

Table 1

PT is the transverse momentum of either of the two photons.

Table 2

PT is the transverse momentum of either of the two photons.